In the present state of the art, MOS devices are not compatible with and therefore cannot directly drive TTL buses because the output impedance of the MOS device is in general very high and it cannot drive the capactive loads of TTL buses. It is necessary to use some elements as an interface between the MOS device and the TTL bus which will translate the high impedance of the MOS output signals to a low impedance drive for the TTL. Known prior art interface devices use voltage comparators which have high input impedances and, in order to enhance the speed of sensing as well as translating the current of the MOS device to a voltage, they require an input resistor, which is undesirable.